No abstract

In this paper, we propose a hybrid method for tracking a bronchoscope that uses a combination of magnetic sensor tracking and image registration. The position of a magnetic sensor placed in the working channel of the bronchoscope is provided by a magnetic tracking system. Because of respiratory motion, the magnetic sensor provides only the approximate position and orientation of the bronchoscope in the coordinate system of a CT image acquired before the examination. The sensor position and orientation is used as the starting point for an intensity-based registration between real bronchoscopic video images and virtual bronchoscopic images generated from the CT image. The output transformation of the image registration process is the position and orientation of the bronchoscope in the CT image. We tested the proposed method using a bronchial phantom model. Virtual breathing motion was generated to simulate respiratory motion. The proposed hybrid method successfully tracked the bronchoscope at a rate of approximately 1 Hz.

Background: Brain metastases develop frequently in patients with non-small cell lung cancer (NSCLC), and the prognosis for these patients is very poor. We evaluated the role of chemotherapy for patients with brain metastases from NSCLC. Methods: We analyzed 30 patients who were discovered to have brain metastases during the diagnosis of 121 patients enrolled in three consecutive clinical trials on advanced NSCLC assessing combination chemotherapy of cisplatin, ifosfamide and irinotecan with rhG-CSF support. Response in the brain lesions was evaluated by contrast-enhanced MRI scans after at least two courses. Results: Fourteen patients achieved a partial response (PR) but there was no change (NC) in 13 patients and progressive disease (PD) in 1. Among patients with extracranial lesions, 18 had a PR and 11 had NC. The response rate in brain metastases was 50.0%, and that in extracranial primary and metastatic lesions was 62.1%. The median duration of response for intra- and extracranial lesions was 140 and 147 days, respectively. After completing chemotherapy, Gamma Knife radiosurgery was performed on 2 patients in remission and 8 patients at disease progression. The median survival time and 1-year survival rate were 382 days and 56.1%, respectively. Conclusions: Both the response rate and survival data in this retrospective study suggest a high degree of activity of this combination chemotherapy in patients with brain metastases from NSCLC.

Pulmonary blood vessels and nodules segmentation method based on local intensity structure analysis and front surface propagation were developed. The method was shown to be feasible for nodule detection and vessel extraction in chest CAD.

This paper presents a new hybrid camera motion tracking method for bronchoscopic navigation combining SIFT, epipolar geometry analysis, Kalman filtering, and image registration. In a thorough evaluation, we compare it to state-of-the-art tracking methods. Our hybrid algorithm for predicting bronchoscope motion uses SIFT features and epipolar constraints to obtain an estimate for interframe pose displacements and Kalman filtering to find an estimate for the magnitude of the motion. We then execute bronchoscope tracking by performing image registration initialized by these estimates. This procedure registers the actual bronchoscopic video and the virtual camera images generated from 3D chest CT data taken prior to bronchoscopic examination for continuous bronchoscopic navigation. A comparative assessment of our new method and the state-of-the-art methods is performed on actual patient data and phantom data. Experimental results from both datasets demonstrate a significant performance boost of navigation using our new method. Our hybrid method is a promising means for bronchoscope tracking, and outperforms other methods based solely on Kalman filtering or image features and image registration.